Return mechanism



Oct. 20, 1953 AC. HUGHES, JR 2,656,178

, RETURN MECHANISM Filed March 14, 1946 2 Sheets-Sheet l FIGJ INVENTOR.ARTHUR C. HUGHES JR.

BY 2Z1 ATTORNEY 2 1953 A. c. HUGHES, JR 2,656, 78

RETURN MECHANISM Filed March 14, 1946 V 2 Sheets-Sheet 2 [N VEN TOR.

' Y ARTHUR- HUGHES JR.

ATTORNEY Patented Oct. 20, 1953 UNEIT STATES PATENT OFFICE RETURNMECHANISM,

Arthur 0. Hughes; Jr., Puente, Calif., assignor;

by mesneassignments, to the United States of'America as represented bythe Secretary Application March 14, 1946, Serial No. 654,494

11 Claims;

This" invention pertains to mechanical 'means" for returning? to centerfrom rotary displacement, and more particularly to such means" leased'.One example of such an operation is fbundin some constructions involvingpotenti ometers. The prior arthas included means for returning tocenter'from a rotary displacement. What is proposed here is a novelmeans for accomplishing this result, one which comprises a single powerspring.

An objectof this invention is to provide a novel device forautomatically returning a'shaft toa predetermined position upon" rotarydisplacement from such predetermined position.

Another objectof this invention is to provide a novel centering devicefor automatically returning to. a predetermined center position a shaftwhich has been subjected to rotary motion.-

Still" another object of this invention is to provide a novel centeringdevice havingasingle springfor automatically returning to apredetermined'center position a shaft which'hasbeen subjected to. rotarymotion, said spring being operable irrespective of the dir'ectionofrotation of said shaft. from said center position;

Other objects and advantages'of"this invention will be apparent from"theaccompanying' claims and description; taken in connection with the"drawings in which:

mantled to facilitate understanding; saidview showing all-of theessential features except the single power spring;

Fig. 2 is a perspective view of the interior elements assemb1edbut doesnot showthe case shaft 16" has fixedly securedto it a first discli,Inherent in shaped as shown in the drawings. p the shape of disc ii"areworkingsurfaces"30; 3|

and 32; the functions of which will be described below under thedescriptionof operation. Also fixedly secured to shaft I6 is a bushing24; the function of which is defined below. As is shown best in Fig. 4,shaft It is supported at one end by a'bearing 33 in such a manner thatshafts l l and it are concentrically and rotatably mounted with respectto each other. The other end of shaft i6 is supported by abearing' 9mounted in a cap 8 oncase l3.

Referring again to Fig. 1 there is shown a' lug l8 secured toshaft Itforanchoring one end of a spiral spring is. Spring 19 appears in'Figs.2, 3 and 4. Also shownin Fig. 1 are a stop 20-, fixedly mounted in casel3, and a seconddisc 2'! with a pin 22 for securing the second end ofspring [9. Disc 2! has a centrally-located circular opening 23 tosupport disc 2i on aforementioned bushing 25 of shaft It. Inherent inthe shape of disc 2| are working-surfaces 3 5', 35',

and 36, corresponding to' surfaces 30, 3| and 32 of disc ll.

Operation of this invention is best understood from a study of Fig. 2.pin [5- normally is held in its zero (or center) position by thecombined restraining action of surface 34 of disc 2i and surface 30of'd-isc l'l. These discs themselves are zero positioned by surfaces 36and 32, of discs 2! and I! respective-' ly, bearing on stop 20 which isfixed with respect to case it. Discs ll and'zl and spring Iii are soinstalled that some stress exists in spring l9 when it is holding thediscs intheir zero posi tion. If through application of an external fromthe input end) disc Ii will be rotated by the action of centering pin l5bearing on surface Since one end of spring is is secured to lug I8 ofshaft l6, which turns with disc l1, and the other end of spring [9 issecured to pin 22 on disc 2|, held fixed by surface 36 bearing'on stop20, spring l9 consequently will be stressed during this operation.During the rotation, there fore, energy is stored in" spring is. Thisstored l1, and consequently is such as to cause rotation in acounterclockwise direction (as seen from the input end) disc Ii willremain without rotation because of sur face 32 bearing on stop Eli, butcentering ltwill' act against surface 3i and cause rotation ofdisc 21As-beiore; ener'gy'isstored in spring" In operation centering [9 duringthis rotary deflection, which energy will restore to the zero positiondisc 2i, centering pin 15 and main shaft ll upon removal of the externalforce.

In the figures the shape of discs I! and 2! and the position of stop 20with respect to the zero position of centering pin l are such as tolimit rotation of main shaft II to 90 degrees either side of its zeroposition. It is emphasized that this is for example only, and that themaximum rotation of main shaft Il may have any value within desirablepredetermined limits without departing from the principles of thisinvention.

What is claimed is:

l. A centering device for returning a shaft to a predetermined centerposition, said device comprising a housing, a shaft rotatably mounted insaid housing, an arm fixedly secured to said shaft, a second shaftrotatably mounted in said housing, a first disc fixedly mounted on saidsecond shaft, a second disc rotatably mounted on said second shaft,means on said housing and said discs for limiting rotation of one ofsaid discs in one direction and for limiting rotation of the other ofsaid discs in the opposite direction, means on said arm and said firstdisc responsive to one direction of rotation of said arm for causingrotation of said first disc, means on said arm and said second discresponsive to the opposite direction of rotation of said arm for causingrotation of said second disc, and means operatively connecting saidsecond-mentioned disc and said second-mentioned shaft for returning saidfirst-mentioned shaft to a predetermined position upon displacementtherefrom.

2. A centering device for returning shaft to a predetermined centerposition, said device comprising a housing, a shaft rotatably mounted insaid housing, an arm fixedly secured to said shaft, a second shaftrotatably mounted within said housing, a first disc fixedly mounted onsaid second shaft, a second disc rotatably mounted on said second shaft,means on said housing and said discs for limiting rotation of saidfirst-mentioned disc in one direction and for limiting rotation of saidsecond-mentioned disc in the opposite direction, a pin mounted on saidarm, means on said first disc to engage said pin for causing rotation ofsaid first-mentioned disc in response to one direction of rotation ofsaid first shaft, means on said second disc to engage said pin forcausing rotation of said second-mentioned disc in response to theopposite direction of rotation of said first shaft, and a springoperatively connecting said second-mentioned disc and saidsecond-mentioned shaft for returning said first-mentioned shaft to apredetermined center position upon displacement of said shaft from saidposition.

3. A centering device for returning a shaft to a predetermined centerposition, said device comprising a housing, a shaft rotatably mounted insaid housing, an arm fixedly secured to said shaft, a second shaftrotatably mounted within said housing, a first disc fixedly mounted onsaid second shaft, a second disc rotatably mounted on said second shaft,a first pin mounted on said housing and means on said first-mentioneddisc for engaging said first pin for limiting rotation of saidfirst-mentioned disc in one direction and means on said second-mentioneddisc for engaging said first pin for limiting rotation of saidsecond-mentioned disc in the opposite direction,

a second pin mounted on said arm and means on said first-mentioned discfor engaging said second pin for rotating said first-mentioned disc inresponse to one direction of rotation of said first shaft and means onsaid second-mentioned disc for engaging said second pin for rotatingsaid second-mentioned disc in response to the opposite direction ofrotation of said first shaft, and a spring operatively connecting saidsecondmentioned disc and said second-mentioned shaft for returning saidfirst-mentioned shaft to a predetermined center position upon angulardisplacement of said shaft from said position.

4. A centering device for returning a shaft to a predetermined centerposition Within a housing comprising, an arm fixedly attached to saidshaft, a stop fixedly attached to said housing, a first member rotatablewithin said housing, disposed coaxially with said shaft and bearing uponsaid arm, a second member rotatable within said housing, disposedcoaxially with said shaft and also bearing on said arm, a springconnected between said first and second members for urging said firstmember and said shaft in a clockwise direction, and for simultaneouslyurging said second member and said shaft in a counterclockwisedirection, first means on said first and second members for engagingsaid stop to limit rotation of said members, second means on said firstand second members for engaging said stop to determine the position ofrest of said members and thereby said center position.

5. A centering device for returning a rotatable main shaft to apredetermined center position within a housing comprising, a stopfixedly attached within said housing, an arm fixedly attached to saidshaft and extending radially therefrom within said housing, a firstsubstantially disc shaped member rotatable within said housing anddisposed coaxially with said shaft, an auxiliary shaft attached to saidmember and extending axially therefrom, a second substantially discshaped member rotatably mounted upon said auxiliary shaft, a spiralspring mounted under stress between a point on said second disc shapedmember and a point on said auxiliary shaft, said spring urging saidfirst member in a clockwise direction and said second member in acounterclockwise direction, first surfaces on said members actingoppositely on said arm, and second surfaces on said members for engagingsaid stop from opposite sides.

6. A centering device for returning a shaft to a predetermined centerposition of rotation comprising, first and second members rotatablymounted about an axis coincident with the rotational axis of said shaft,a spring member connecting said first and second members and urgingrelative rotation between said first and second members, a stop fixed inposition relative to said center position of said shaft, each of saidfirst and second members being formed with at least one stop engagingmeans for limiting rotation of said first and second members byengagement with said stop, a third member secured to said shaft androtatable therewith, said first member being formed with means engagingsaid third member upon rotation of said shaft in a first direction fromsaid center position to cause said first member to rotate with saidshaft in said first direction, said second member being formed withmeans engaging said third member upon rotation of said shaft in theopposite direction from said center position to cause said second memberto rotate with said shaft in said second direction.

7. A centering device for returning a shaft to a predetermined centerposition of rotation comprising, first and second members rotatablymounted about an axis coincident with the rotational axis of said shaft,a spring member connecting said first and second members and urgingrelative rotation between said first and second members, said firstmember being urged in a clockwise direction and said second member beingurged in a counterclockwise direction, a stop fixed in position relativeto said center position of said shaft, each of said first and secondmembers being formed with a stop engaging means for limiting rotation ofsaid first and second members in clockwise and counterclockwisedirections, respectively, by engagement with said stop thereby todetermine the position of rest of said first and second members, a thirdmember secured to said shaft and rotatable therewith, said first memberbeing formed with means engaging said third member upon rotation of saidshaft in a counterclockwise direction from said center position to causesaid first member to rotate with said shaft in said counterclockwisedirection, said second member being formed with means engaging saidthird member upon rotation of said shaft in a clockwise direction fromsaid center position to cause said second member to rotate with saidshaft in said second direction.

8. A centering device as in claim 7 wherein said means on said first andsecond members engaging said third member simultaneously engage saidthird member When said shaft is in said center position and said firstand second members are in their respective rest positions.

9. A centering device for returning a shaft to a predetermined centerposition of rotation and for limiting the rotation of said shaft fromsaid center position comprising, first and second members rotatablymounted about an axis coincident with the rotational axis of said shaft,a spring member acting between said first and. second members and urgingrelative rotation of said first and second members, said first memberbeing urged in a clockwise direction relative to said second member,said first and second members each being formed with an arcuate way ofpredetermined length, a stop member fixed in position relative to saidcenter position of said shaft and disposed in said ways of said firstand second members, rotation of said first and second members beinglimited by engagement of said stop member with the ends of said ways, athird member secured to said shaft and rotatable therewith, said firstmember being formed with means engaging said third member upon rotationof said shaft in a counterclockwise direction from said center position,said second member being formed with means engaging said third memberupon rotation of said shaft in a clockwise direction from said centerposition.

10. A centering device for returning a shaft journaled in a housing to apredetermined center position with respect to said housing com--prising, a stop fixed to said housing, a first means adapted to urge theshaft in a clockwise direction relative to the housing, a second meansadapted to urge the shaft in a counterclockwise direction relative tothe housing, spring means acting between said first and second means andurging relative rotation of said first and second means, and means onsaid first and second means for engaging said stop to determine saidcenter position.

11. A centering device for returning a shaft journaled in a housing to apredetermined center position with respect to said housing comprising,an arm fixedly attached to said shaft, a stop fixedly attached to saidhousing, a first member adapted to bear upon said arm to urge the shaftin a clockwise direction relative to said housing, a second memberadapted to bear upon said arm to urge the shaft in a counterclockwisedirection relative to said housing, spring means acting between saidfirst and second members and urging relative rotation of said first andsecond members, means on said first and second members for engaging saidstop to limit the rotation of said members, and additional means on saidfirst and second members for engaging said stop to determine said centerposition.

ARTHUR C. HUGHES, JR.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,192,731 Batchelder July 25, 1916 1,795,149 Shivers Mar. 3,1931 2,023,235 Le Count Dec. 3, 1935 2,195,084 Eklund Mar. 26, 19402,336,307 Slye Dec. 7, 1943 2,408,274 Schleicher Sept. 24, 19462,429,313 Gilbert Oct. 21, 1947

